Drive system with ventilation

ABSTRACT

A drive system, in particular a drive system of a wheel hub, for a motor vehicle, in particular an electric and/or hybrid motor vehicle, the drive system including an electric motor. In order to prevent moisture from accumulating in an internal chamber ( 1 ) of the drive system, the drive system includes a ventilation device ( 20 ) for aerating and de-aerating the interior chamber ( 1 ) of the drive system. The ventilation device ( 20 ) includes at least one air supply device ( 21 ) for supplying air into the internal chamber ( 1 ) of the drive system and at least one air removal device ( 22 ) for removing air from the internal chamber ( 1 ) of the drive system.

The present invention relates to a drive system for a vehicle, in particular for an electric and/or a hybrid vehicle.

BACKGROUND

Interest in electric vehicles has increased more and more in recent years, in particular due to a growing environmental awareness.

Central and wheel-proximal electric motors as well as electric wheel hub drives, among other things, may be used in electric cars. Electric wheel hub drives are a special design of an electric motor. An electric wheel hub drive includes an electric motor which is built directly into a wheel of a vehicle and simultaneously supports the wheel hub in such a way that a part of the motor rotates together with the wheel.

In an internally rotating wheel hub drive, a so-called internal rotor, the rotor may be situated, for example, inside the stator. In an externally rotating wheel hub drive, a so-called external rotor, the rotor may be situated, for example, outside the stator.

Since wheel-proximal electric motors and wheel hub drives are situated in the surroundings of a vehicle wheel, they may be exposed to high humidity or even moisture, in particular during rainy weather.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a drive system, in particular a wheel hub drive system, for a vehicle, in particular for an electric and/or hybrid vehicle, having at least one drive system internal chamber which includes an electric motor having a stator and a rotor.

The present invention provides that the drive system includes a ventilation device for aerating and de-aerating the drive system internal chamber of the drive system, the ventilation device including at least one air supply device for supplying air to the drive system internal chamber and at least one air removal device for removing air from the drive system internal chamber.

Within the scope of the present invention, air may be understood to be a natural air atmosphere or ambient air as well as an artificial atmosphere having, for example, a high concentration of inert gas. In the specific embodiment explained below, in particular, in which the drive system is designed for active aeration during maintenance work, an inert gas or a gas mixture containing inert gas may be used for active ventilation. For example, nitrogen, argon and/or helium, in particular nitrogen, may be used as inert gas.

A targeted air exchange between the drive system and its surroundings may be advantageously ensured by the ventilation device according to the present invention. Pressures which may build up in the drive system, in particular due to climatic conditions and/or temperature fluctuations, for example in the event of a cool external temperature and an elevated inner temperature which results in significant air expansion, for example due to braking actions with the aid of a friction brake, may be advantageously compensated with the aid of the ventilation device. Thus, pressure-induced and possibly heat-induced damage to sensitive drive system elements may be prevented, for example the lifting of seals. In addition, moisture which penetrates the drive system, possibly due to humidity condensation or possible leakages, may be advantageously removed with the aid of the ventilation device.

Within the scope of one specific embodiment, the air supply device(s) is/are situated above a drive axis of the drive system. For example, the air supply device(s) may be situated in relation to the drive axis in a position range from ≧9 o'clock to ≦3 o'clock, in particular from ≧10 o'clock to ≦2 o'clock, for example from ≧11 o'clock to ≦1 o'clock, for example approximately at 12 o'clock. Situating the air supply devices above the drive axis has the advantage that less spray water tends to be applied to this area, and an introduction of moisture may thus be reduced or even prevented.

Within the scope of another specific embodiment, the air removal device(s) is or are situated below a drive axis of the drive system. For example, the air removal device(s) may be situated in relation to the drive axis in a position range from ≧3 o'clock to ≦9 o'clock, in particular from ≧4 o'clock to ≦8 o'clock, for example from ≧5 o'clock to ≦7 o'clock, for example approximately at 6 o'clock, Situating the air removal devices below the drive axis has the advantage that moisture tends to be deposited in this area and may thus be particularly effectively removed from this area.

Air supply devices situated above the drive axis and air removal devices situated below the drive axis have, in combination, the advantage that a greater amount of flow passes through the volume of the drive system internal chamber, and the flowing air is able to absorb more liquid and transport it out of the system.

Within the scope of another specific embodiment, the air supply device(s) includes or include at least one filter, in particular a particle filter and/or a moisture filter and/or a gas filter. This makes it possible to advantageously prevent contamination and/or moisture and/or chemically aggressive gases from being introduced into the drive system internal chamber of the drive system. A filter based on a water-impermeable but vapor diffusion-open diaphragm, for example, may be used to filter out moisture in the liquid aggregate state and/or particles. For example, a diaphragm based, for example, on polytetrafluoroethylene (PTFE), from, for example, the Gore Company (“Gore-Tex”), Germany, may be used as a filter for removing moisture in the liquid aggregate state and/or particles.

Within the scope of another specific embodiment, the air supply device(s) includes or include at least one dryer. The dryer may be based, for example, on water condensation and, for example, remove moisture from air due to the fact that the air is cooled to a lower temperature. For example, an air conditioning system of the vehicle may function as the dryer. However, it is also possible for the dryer to be designed on the basis of a physically and/or chemically water-absorbing material. If necessary, a dryer of this type may simultaneously function as a filter, or a filter of this type may simultaneously function as a dryer. Consequently, the air supply device(s) may also have at least one combined filter-dryer unit.

The air supply device(s) may furthermore include an air supply line, for example an air supply hose.

For this purpose, the air supply device(s) may be designed in such a way that air may be passively and/or actively supplied to the drive system internal chamber. The air supply device(s) may thus be designed as active and/or passive air supply device(s). For example, the air supply device(s) may be completely active, temporarily active and otherwise passive or completely passive air supply device(s).

A passive design of the air supply device(s) is explained in greater detail below in connection with a check valve system.

An active design of the air supply device(s) may be carried out, for example, by the fact that the air supply device is permanently or temporarily connected or connectable to a ventilation system of the vehicle or to a maintenance ventilation system. An active ventilation of the drive system internal chamber may thus be advantageously achieved. The active ventilation may take place, for example, using a ventilation system provided in the vehicle and/or a maintenance ventilation system connected during maintenance.

Within the scope of another specific embodiment, the air supply device(s) is or are designed as active or temporarily active air supply devices for the at least temporary, active supply of air to the drive system internal chamber. In particular, the air supply device(s) may be temporarily connectable or permanently connected to a ventilation system of the vehicle, for example an air conditioning system of the vehicle. Alternatively or additionally, the air supply device(s) may be temporarily connectable to a maintenance ventilation system. A cleaning/drying of the system may thus advantageously take place without having to disassemble the system.

Within the scope of another specific embodiment, air from a vehicle interior, for example from a passenger cell, or a storage compartment, for example a trunk, may be supplied to the drive system internal chamber with the aid of the air supply line.

Within the scope of another specific embodiment, the air supply device(s) is or are situated on a stationary, i.e., non-rotatable, drive system element of the drive system, for example on a drive system element of the drive system which is, in particular, rotatably fixedly connected to the stator of the electric motor, for example on a stator retaining plate.

The air removal device(s) may also be situated on the same or on a different stationary drive system element of the drive system, for example on a stationary drive system element of the drive system which is, in particular, rotatably fixedly connected to the stator of the electric motor, for example on a stator retaining plate.

However, since the air removal device(s) does/do not have to be connected to additional elements, for example the vehicle, the air removal device(s) may also be readily situated on a rotatable drive system element of the drive system, for example on a rotatable drive system element of the drive system which is, in particular, rotatably fixedly connected to the rotor of the electric motor, for example a wheel rim, a cover or a rotor support.

Within the scope of another specific embodiment, the air supply device(s) includes or include an air supply connecting element for the airtight connection of the air supply device to the drive system internal chamber. For example, the air supply connecting element may be fastenable or fastened to a recess in a wall delimiting the drive system internal chamber, for example in a stator retaining plate, in such a way that air is able to enter the drive system element internal chamber through the air supply connecting element, the area between the air supply connecting element and the wall delimiting the recess and the drive system internal chamber being airtight and, in particular, also water-tight.

Within the scope of another specific embodiment, the air removal device(s) includes or include an air removal connecting element for the airtight connection of the air removal device to the drive system internal chamber. For example, the air removal connecting element may be fastenable or fastened to a recess in a wall delimiting the drive system internal chamber, for example in the stator retaining plate and/or in the wheel rim, in the cover or in the rotor support, in such a way that air is able to exit the drive system element interior through the air removal connecting element, the area between the air removal connecting element and the wall delimiting the recess and the drive system internal chamber being airtight and, in particular, also water-tight.

A directed air movement and thus a targeted exchange of air may advantageously be achieved by using valves, in particular check valves, in the air supply devices and/or air removal devices.

For example, the air supply devices may be provided with valves which ensure that air is able to only flow in but not flow out, while the air removal devices may be provided with valves which ensure that air is able to only flow out but not flow in. When the air in the interior of the system is heated, the air may thereby be forced to flow out through the preferably lower air removal devices and remove any water and/or dirt which may be located in the system. Upon cooling, the air removal device(s) may be blocked, and air may be drawn back in through the, in particular, upper air supply device(s).

Within the scope of another specific embodiment, the air supply device(s) includes or include a valve, in particular a check valve. In particular, the valve or the check valve of the air supply device may be designed to allow air to flow into the drive system internal chamber and to prevent air from flowing out of the drive system internal chamber.

Within the scope of another specific embodiment, the air removal device(s) includes or include a valve, for example a check valve. In particular, the valve or the check valve of the air removal device may be designed to allow air to flow out of the drive system internal chamber and to prevent air from flowing into the drive system internal chamber.

In particular, a water-impermeable but vapor diffusion-open diaphragm, which is air-permeable in only one direction and air-impermeable in the other direction, may be used as the valve, in particular the check valve. For example, a diaphragm based, for example, on polytetrafluoroethylene (PTFE), from, for example, the Gore company (“Gore-Tex”), Germany, may be used as the valve, in particular the check valve.

The ventilation device may include, in particular, multiple air removal devices. It is possible for only one air supply device but multiple air removal devices to be provided, for example in the form of valves, in particular check valves.

Alternatively or in addition to multiple air removal devices, the ventilation device may include multiple air supply devices, for example in the form of valves, in particular check valves.

Within the scope of another specific embodiment, the drive system also includes a friction brake. In particular, the friction brake may be integrated within a vehicle wheel, in particular within the electric motor, for example within the rotor of the electric motor. The friction brake may be, for example, a drum brake or a disc brake.

The drive system internal chamber is preferably at least partially, in particular completely, designed as a closeable or closed chamber. Closeable may be understood to mean that the drive system internal chamber is designed to be able to be temporarily opened and then closed again. For example, the drive system internal chamber may be open during assembly and/or maintenance and closeable after assembly and/or maintenance.

Within the scope of another specific embodiment, the drive system internal chamber surrounds a gap, in particular an air gap, between the stator and the rotor of the electric motor, and/or a friction brake of the drive system.

If necessary, the drive system may also include two or more drive system internal chambers. For example, the drive system may include a drive system internal chamber which surrounds the gap, in particular the air gap, between the stator and the rotor and may also include another drive system internal chamber which surrounds the friction brake. It is not necessary to equip the drive system with two ventilation systems. Instead, the drive system internal chambers may be connected in series between the air supply device(s) and the air removal device(s), it being possible to provide at least one airlock between the drive system internal chambers. The airlock(s) may be provided with a similar design as the air supply devices.

For example, an airlock may include a valve, in particular a check valve, and/or an airlock connecting element for the airtight connection of the airlock between two drive system internal chambers, and/or a filter, for example a particle filter and/or a moisture filter and/or a gas filter, and/or a dryer.

In particular, an airlock may include or consist of a valve, for example a check valve, which, in particular, permits air to flow into the downstream drive system internal chamber and prevents air from flowing out of the downstream drive system internal chamber into the upstream drive system internal chamber. A drive system element chamber which surrounds the gap between the rotor and the stator is preferably an upstream drive system element chamber, and/or the drive system element chamber which surrounds the friction brake is a downstream drive system element chamber. The drive system element chamber which has the moisture-sensitive components may thus advantageously be provided with fresher or dryer air.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is explained in greater detail below with reference to the appended drawing. The drawing and its description are intended to be used to illustrate the subject matters of the present invention and not to be used to limit the present invention in any way.

FIG. 1 shows a schematic cross section of one specific embodiment of a drive system according to the present invention, including a ventilation device.

DETAILED DESCRIPTION

FIG. 1 shows a specific embodiment of a drive system according to the present invention for an electric and/or hybrid vehicle which is designed, in particular, as a wheel hub drive system and has a drive system internal chamber 1.

FIG. 1 shows that drive system internal chamber 1 surrounds an electric motor having a stator 10 and a rotor 11. Stator 10 is situated in a stationary, i.e., non-rotatable, manner, and rotor 11 is rotatably situated, in particular around a drive axis A of the drive system.

FIG. 1 shows that a gap S, in particular an air gap, is present between stator 10 and rotor 11. For efficiency reasons, the gap between stator 10 and rotor 11 is designed to be so small that a grinding of rotor 11 against stator 10 is nevertheless prevented.

FIG. 1 shows that the drive system internal chamber within the scope of the illustrated specific embodiment also surrounds a friction brake 13 a, 13 b, 13 c, which is designed as a drum brake and which includes a brake drum 13 a, brake shoes 13 b and a brake cylinder 13 c.

FIG. 1 furthermore illustrates that stator 10 is, in particular, rotatably fixedly connected to a stationary inner ring 14 a of a wheel bearing via a stator retaining plate 12. The wheel bearing furthermore has an outer ring 14 b which is rotatably supported via rolling bodies 14 c. Rolling bodies 14 c are situated in rolling bearing cages, the wheel bearing being braceable with the aid of a bracing device 14 e which interacts with a rolling bearing inner ring 14 d. The wheel bearing also has fastening elements 14 f for fastening the wheel bearing to the vehicle.

FIG. 1 also shows that rotor 11 is connected to rotatable outer ring 14 b of the wheel bearing via a rotor support 15. The rotor support is connected to rotatable outer ring 14 b of the wheel bearing as well as to a wheel rim (not illustrated) with the aid of a screw connection 16. Rotor support 15 is also connected to brake drum 13 a with the aid of another screw connection 17. However, brake shoes 13 b and brake cylinder 13 c are connected to stator retaining plate 12.

FIG. 1 furthermore shows that the drive system has a cover 18. This cover is situated, in particular, on the outside and may be used to temporarily open the drive system internal chamber during maintenance work.

FIG. 1 furthermore shows that stator 10 has two winding head areas 10 a in addition to a stator lamination stack 10 situated in the central area.

FIG. 1 shows, in particular, that the drive system has a ventilation device 20 for aerating and de-aerating drive system internal chamber 1, which includes an air supply device 21 for supplying air to drive system internal chamber 1 and an air removal device 22 for removing air from drive system internal chamber 1.

FIG. 1 illustrates that air supply device 21 is situated above drive axis A of the drive system, in particular approximately in the 12-o'clock position, while air removal device 22 is situated below the drive axis of the drive system, in particular approximately in the 6-o'clock position. Within the scope of the illustrated specific embodiment, both air supply device 21 and air removal device 22 are fastened to a stationary drive system element of the drive system, namely stator retaining plate 12. Air supply device 21 includes an air supply connecting element 21 a for the airtight connection of air supply device 21 to drive system internal chamber 1, and air removal device 22 includes an air removal connecting element 22 a for the airtight connection of air removal device 22 to drive system internal chamber 1.

FIG. 1 shows that air supply device 21 furthermore has a hose-type air supply line 21 b via which air supply device 21 may be temporarily connected to a ventilation system of the vehicle, for example an air conditioning system of the vehicle, or a maintenance ventilation system, or which may be temporarily or permanently connected to a vehicle interior, for example a passenger cell or a storage compartment, for example a trunk, of the vehicle, in particular to actively and/or passively supply air to drive system internal chamber 1.

FIG. 1 finally shows that air removal device 22 includes a valve, in particular a check valve 22 b. The valve or check valve 22 b is designed to allow air to flow out of drive system internal chamber 1 and to prevent air from flowing into drive system internal chamber 1. The valve is connected to air removal connecting element 22 a with the aid of a connecting piece 22 c.

LIST OF REFERENCE NUMERALS

-   1 Drive internal chamber -   10 Stator of the electric motor, in particular a stator lamination     stack -   10 a Winding head area of the stator -   11 Rotor of the electric motor -   A Drive axis -   S Gap between the stator and rotor of the electric motor -   12 Stator retaining plate -   13 a Brake drum of the friction brake -   13 b Brake shoes of the friction brake -   13 c Brake cylinder of the friction brake -   14 a Stationary inner ring of the wheel bearing -   14 b Rotatable outer ring of the wheel bearing -   14 c Rolling body of the wheel bearing -   14 d Rolling bearing inner ring -   14 e Rolling bearing bracing device -   14 f Fastening element for fastening the wheel bearing to the     vehicle -   15 Rotor support -   16 Screw connection -   17 Screw connection -   18 Cover -   20 Ventilation device -   21 Air supply device -   21 a Air supply connecting element -   21 b Air supply line -   22 Air removal device -   22 a Air removal connecting element -   22 b Check valve of the air removal device -   22 c Connecting piece of the air removal device 

What is claimed is: 1-10. (canceled)
 11. A drive system for a vehicle, the drive system having at least one drive system internal chamber, the drive system comprising: an electric motor having a stator and a rotor; and a ventilation device for aerating and de-aerating the drive system internal chamber, the ventilation device including at least one air supply device for supplying air to the drive system internal chamber and at least one air removal device for removing air from the drive system internal chamber.
 12. The drive system as recited in claim 11 wherein the air supply device is situated above a drive axis of the drive system or the air removal device is situated below the drive axis.
 13. The drive system as recited in claim 11 wherein the air supply device include at least one filter or at least one dryer.
 14. The drive system as recited in claim 13 wherein the air supply device includes a particle filter or a moisture filter or a gas filter.
 15. The drive system as recited in claim 11 wherein the air supply device is designed as an active or temporarily active air supply device for at least temporarily actively supplying air to the drive system internal chamber.
 16. The drive system as recited in claim 15 wherein the air supply device is temporarily connectable or permanently connected to a ventilation system of the vehicle or is temporarily connectable to a maintenance ventilation system.
 17. The drive system as recited in claim 16 wherein the sir supply device is connected to an air conditioning system of the vehicle.
 18. The drive system as recited in claim 11 wherein air from a vehicle interior, is suppliable to the drive system internal chamber with the aid of the air supply device.
 19. The drive system as recited in claim 18 wherein the air is from a passenger cell or a storage compartment.
 20. The drive system as recited in claim 19 wherein the air is from a trunk.
 21. The drive system as recited in claim 11 wherein the air supply device is situated on a stationary drive system element of the drive system.
 22. The drive system as recited in claim 21 wherein the stationary drive system element of the drive system is fixedly connected to the stator of the electric motor.
 23. The drive system as recited in claim 22 wherein the air supply device is on a stator retaining plate.
 24. The drive system as recited in claim 11 wherein the air supply device includes an air supply connecting element for the airtight connection of the air supply device to the drive system internal chamber, or the air removal device includes an air removal connecting element for the airtight connection of the air removal device to the drive system internal chamber.
 25. The drive system as recited in claim 11 wherein the air supply device includes a valve, or the air removal device includes a further valve.
 26. The drive system as recited in claim 25 wherein the air removal device includes a check valve.
 27. The drive system as recited in claim 25 wherein the air removal device includes the further valve, the further valve being designed to allow air to flow out of the drive system internal chamber and to prevent air from flowing into the drive system internal chamber.
 28. The drive system as recited in claim 25 wherein the air supply device includes a check valve.
 29. The drive system as recited in claim 25 wherein the air supply device has the valve, the valve allowing air to flow into the drive system internal chamber and to prevent air from flowing out of the drive system internal chamber.
 30. The drive system as recited in claim 11 further comprising a friction brake.
 31. The drive system as recited in claim 11 wherein drive system internal chamber surrounds a gap between the stator and the rotor of the electric motor or surrounds a friction brake.
 32. The drive system as recited in claim 31 wherein the gap is an air gap.
 33. A wheel hub drive system comprising the drive system as recited in claim
 11. 34. An electric or hybrid vehicle comprising the drive system as recited in claim
 11. 